If it helps, I have tons of code that tests for iterators using:
iter(obj) is obj
That has been a documented requirement for the iterator protocol
forever. Its in the PEP.
"A class that wants to be an iterator should implement two methods: a
next() method that behaves as described above, and an __iter__() method
that returns self."
https://www.python.org/dev/peps/pep-0234/
We have objects such that:
iter(obj)
returns an iterator, but aren't themselves iterators. The most common
example of that would be, I think, classes that define __iter__ as a
generator method:
class A:
def __iter__(self):
for x in range(10):
yield x
Then we have actual iterators, like iter(A()). They define `__iter__`
that returns self.
I don't know what I would call an object that only has __next__,
apart from "broken" :-(
--
Steve
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